The International Cessna^® 170 Association

Looking for advice. 0 300 with about 300hrs. Since major. I had my mechanics looking for an oil leak and they found a crack around the flange of # 3 cylinder, thus no more looking! What is the best course of action?
Scott

Sorry to hear about the bad case but better to find it down here than...up there.

As far as best course of actions. I'm going to guess that people will say "That depends".

What's more important to you: time or money?

Depends on how much of each. I,m more interested in the best value,because I do have another 170 available to fly.
Scott

A man with TWO 170s. I can respect that

I'd talk to your mechanic about replacing the case.
300 hours isn't a lot of time for an O300.
If the motor has good compression and no other problems, that would be the most economical (unless I am really underestimating the hours involved). It's not an overhaul, it would be a repair.

OR this might be a good time to think about a vacuum system (O300D)

OR this might be a good excuse to put a bigger motor in...

There are much smarter people on this forum than me tho and they will be able to provide more insight.

Welcome to the forum by the way!

You have the same problem I had about 20 years ago While looking for oil leaks from my O-300A engine IA spotted a crack. Engine at that time was +/- 500 SMOH. UGH. On IA's advice we shipped both case halfs to Divco in OK. They called back with the bad news the cracked case half was unrepairable The good news they had a replacement in stock. So, bought replacement part, put it back together, and was back in the air in three weeks. Ran that engine for another 1000 hours with no problems. Out of pocket cost was price of case half and my IA's labor to R&R engine.

As we speak...a good friend we all know... just bought a new (to him) plane. It's history is that it also had a O-300 with oil leaks....some of them at cylinder-base/thru-bolts. The engine had only 70 TSMOH. The shop recommended it be sent to Custom Airmotive in OK....who took it apart to discover the "overhaul" done 70 hours earlier.... had been done with lots of used, out-of-spec parts. The main bearing saddles were cracked, likely due to undersized bearings being overtorqued on a run-out crank and camshaft. They recommended Divco to repair by welding, and they contacted the San Antonio shop who had "overhauled" the engine....which promptly admitted their sorry work and rather than deal with FAA and lawyers agreed to pay the OK shop's bills for the repair.
The case halves were repaired by welding, the engine reassembled with new crank/cam/bearings/gears/etc... the 70 hr since new cyls re-installed, and the engine has now run another 130 perfectly without a single oil leak. The only drawback is.... the "repair" does not reset the clock on the overhaul....but the engine is now a fine engine.
Those leaks can lead to cracked cases caused by improper previous work, including cylinder replacements which suffered improperly re-torque base nuts/thru-bolts. Be thorough and careful when evaluating this problem, and engage the services of an ethical professional who knows these engines.

The overhaul was done by a very reputable shop in the northeast, so I don't think there are any subpar issues and because money is always an issue, I think the repair avenue is the way to go, but 182 performance would be nice!
Scott

My ears perked up when "182 performance" was mentioned and I connected it to Del-Air selling off invertory. It might be the best timing to spring for the 0-360 Del-Air conversion. I understand it's the only game in town right now and "Used" 0-360 conversion is not a good option.

What do you mean by USED 0-360 not a good option? Just curious as I may consider this at TBO. Steve

I have an 0-300 case and crank for sale if you still need one.

Thanks, but I have a yellow tagged case on the way. With luck, I will have this resolved soon!
Thanks to all, you guys are great!
Scott

Just to let everyone know....I have two 145 cases on the shelf if anyone needs one.